I've written two recent blog posts on Fondly, Pennsylvania, the archives and conservation blog of the Historical Society of Pennsylvania, about collapses that happen to have anniversaries this week.
As you may know, today is the 150th anniversary of South Carolina's secession from the United States. You can read about this and other events leading up to the Civil War in my post about the papers of President James Buchanan.
This week is also the 80th anniversary of the failure of Bankers Trust Company, which on December 22, 1930 became the first large Philadelphia bank to fail during the Great Depression. I am researching the Bankers Trust story as part of my work with the Greenfield digital history project.